Smooth starting is achieved by arresting the steady decrease in the ignition angle of the current control elements upon attaining a predetermined limiting current value. It is common practice in circuit arrangements arresting the steady decrease of the ignition angle of the current control elements, as shown in Fairford Electronics Ltd., Great Britain, Application Note 1984, for the so-called voltage ramp, to be arrested upon the occurrence of the limiting current value until the current being carried has decreased again as a result of a further acceleration of the machine. Current limiting of this type is possible in three-phase systems through evaluation of the variation of the three-phase full-wave rectified current patterns. In the three-phase case the contradictory requirements on the one hand, that the instantaneous current value must be determined in a very short time; and on the other, that in order to achieve the desired reduction in current, the control signal must be kept sufficiently long because of the discontinuous firing of the solid-state power devices, can be satisfied. However the hardware to implement this known procedure is expensive. In the case of single-phase application or measurement, for a three-phase motor, the hardware is less expensive; however the selection of a suitable smoothing time constant is critical to proper operation.